1. Field of the Invention
This invention relates to a recording medium on which files for audio data to be processed on a real-time basis or data of motional pictures (video data) and files for still picture data, character data or program data which are not required to be processed on a real-time basis are recorded while mixed with each other, and an information processing device for executing a different processing mode in accordance with a file attribute information recorded on the recording medium.
2. Description of Related Art
It has been well known that a CD-ROM (Compact Disc Read Only Memory) is standardized on the basis of a CD for music (Compact Disc Digital Audio: hereinafter referred to as "CD-DA").
First, a physical format of a CD-ROM will be briefly described.
The physical format is defined as a format with which data can be read out at least physically when a CD-ROM disc is loaded into a CD-ROM driver. A disc may be designed to contain music (digital audio) tracks or data tracks whose maximum number is equal to 99. Information on these tracks is recorded at a head portion which is so-called TOC (Table of Contents), that is, at the innermost peripheral portion of the disc. The portion at which the TOC is recorded is called as "Lead In Track". On the other hand, the last track of the disc, that is, the portion at which the last musical piece is finished is called as "Lead Out Track".
For the CD-DA, stereo signals are digitally recorded at a sampling rate of 44.1 kHz for 16 bits, and thus data of 2(stereo).times.2(16 bits).times.44,100=176,400 bytes totally are recorded for one second. For the CD-ROM, a sector is treated as a minimum unit for processing. The sector is obtained by dividing one second into 75 equi-segments, and thus one sector comprises 2,352 bytes.
In a CD-ROM MODE-1 as shown in FIG. 1, one sector includes SYNC data (12 bytes) for synchronization, a header (4 bytes), an ECC (Error Correction Coding:276 bytes) for correcting an error, an EDC (Error Detect coding:4 bytes), etc., and thus the residual 2048 bytes of one sector are used to record user data. With respect to audio data, image data, etc. on which a strict error correction using data interpolating processing is not required to be conducted, the ECC and EDC are omitted, and an area of the residual 2,336 bytes excluding the SYNC and the header is used to record the user data in one sector. This format is called as "CD-ROM MODE-2".
CD-I (Compact Disc Interactive) and CD-ROM/XA (CD-ROM extended Architecture) are provided as a superordinate standard. In these CD-I and CD-ROM/XA, the CD-ROM MODE-2 is redefined to add formats of FORM-1 and FORM-2 as shown in FIG. 1. For the CDI, CPU, OS (Operating System), etc. are provided as operating environments for a CD player, that is, environments under which the CD player is allowed to execute applications. The CD-ROM/XA is obtained by removing the provision on these operating environments and directly using and standardizing the physical format for the CD-I or the audio data format.
In the CD-I and CD-ROM/XA as described above, in a case where audio data for which a reproduction processing on real-time basis is required and other data for which the reproduction processing on real-time basis is not required are recorded on a disc while mixed with each other, these data are recorded while interleaved every sector unit in advance. That is, the audio (sound) data A and still picture data V or data D such as other text data are mutually interleaved with each other on sector-unit basis so that neither underflow nor overflow occurs in a process of reproduction processing, and these data are intermittently recorded on a disc in the state where they are interleaved on sector-unit basis as described above.
As described above, the data to be subjected to the reproduction processing on real-time basis (hereinafter referred to as "real-time reproduction processing" and the data for which no real-time reproduction processing is required) are alternately recorded every sector unit, and thus it is required to record identification information for indicating the attribute of the data on each sector.
In order to satisfy this requirement, the following manners have been conventionally made in the FORM-1 and FORM02 of the CD-ROM MODE-2. That is, a submode area (8 bits) is provided in a subheader (8 bytes) of each sector and 1 bit of the submode is allocated as a Real-Time Flag. On the basis of judgment as to whether the Real-Time Flag thus allocated is "0" or "1", it is judged every sector unit whether data should be subjected to the real-time reproduction processing, and a processing mode is switched in accordance with the above judgment result.
As described above, in the FORM-1 and FORM-2 of the CD-ROM MODE-2 which are provided in the conventional CD-I and CD-ROM/XA, the Real-Time Flag (identification information) representing information as to whether data should be subjected to the real-time reproduction processing must be recorded for each sector, so that data management is complicated. In addition, since the processing mode must be switched every sector unit on the basis of the judgment as to whether the data should be subjected to the real-time reproduction processing, so that the processing itself is complicated.
Further, in a conventional CD-ROM file system, when audio or image data are subjected to the real-time reproduction processing, the data are reproduced after all of file data required are stored in a main memory, the data processing is restricted by capacity of the main memory, and a long-time data reproduction cannot be performed.